Organic light emitting diode (OLED) light sources and displays are known. Such light sources and displays are constructed by depositing and treating multiple layers of materials such as organic materials on a substrate. When a current is passed through the multiple layers of organic materials, light is emitted. The color of light is dependent on the type of materials. As used herein the term flat panel light source refers to displays, backlights, and area illumination devices.
The deposition of the layers of organic materials in an OLED device is difficult. The materials are sensitive to moisture and must be carefully patterned at a high resolution to enable a pixilated display capable of, for example, displaying images. Small molecule OLED materials are typically deposited by evaporation from a source onto a substrate. It is known to register a mask having extended linear structures with variable widths with a substrate and to translate a source of material past the substrate to form a patterned deposition. This process is described in detail in “Linear Source Deposition of Organic Layers for Full Color OLED” by VanSlyke et al. SID 02 Digest, Vol. 33, No. 2, pp 886–889, 2002. However, this technique is not convenient for continuous manufacture.
U.S. Patent Application No. 2002/0179013A1, published Dec. 5, 2002 by Kido et al. discloses a vapor deposition system that includes a plurality of vapor deposition chambers through which discrete substrates and masks are passed to receive successive deposits of vapor deposition material. A problem with this approach is the complication of holding and transporting individual discrete substrates.
U.S. Pat. No. 6,328,806 issued Dec. 11, 2001 to Eller discloses a device for treating a band-shaped substrate with a gas. A continuous band-shaped substrate is passed by a deposition station that includes a source of gaseous material and a continuous band-shaped mask. A problem with this approach is the difficulty in making, handling, and cleaning a continuous mask through which multiple depositions are to be made, and the difficulty in maintaining alignment with a continuous substrate and continuous mask for multiple depositions. In addition, continuous masks are expensive to manufacture.
There is a need therefore for an improved continuous method for the application of patterned materials for making flat panel light sources.